A blacktop material that is laid while hot always comprises a mix of a mineral aggregate skeleton coated in hot bitumen. Attempts are made to keep its temperature high until it has finished being laid, which generally occurs within the two hours following fabrication and transport to the site where it is laid. This laying consists in distributing the mixture over the surface to be covered in a layer of thickness that is defined, regular, and uniform, e.g. in order to constitute a layer of a roadway (a top layer or a bed layer) or of a similar work. The hot blacktop material is generally laid using a road surfacing machine which performs all of the mechanical functions that are required, and that are accompanied in the final stage by passing compactors over the freshly-spread layer, which compactors serve to densify the mixture.
During these various stages, it can happen that the temperature of the mixture drops below the acceptable limit for satisfactory laying. In addition, it can be advantageous to fabricate paving material at relatively low temperature, for example as described in the patent application filed on the same day as the present patent application by the same Applicant.